'\" et
.TH STRFMON "3P" 2017 "IEEE/The Open Group" "POSIX Programmer's Manual"
.\"
.SH PROLOG
This manual page is part of the POSIX Programmer's Manual.
The Linux implementation of this interface may differ (consult
the corresponding Linux manual page for details of Linux behavior),
or the interface may not be implemented on Linux.
.\"
.SH NAME
strfmon,
strfmon_l
\(em convert monetary value to a string
.SH SYNOPSIS
.LP
.nf
#include <monetary.h>
.P
ssize_t strfmon(char *restrict \fIs\fP, size_t \fImaxsize\fP,
    const char *restrict \fIformat\fP, ...);
ssize_t strfmon_l(char *restrict \fIs\fP, size_t \fImaxsize\fP,
    locale_t \fIlocale\fP, const char *restrict \fIformat\fP, ...);
.fi
.SH DESCRIPTION
The
\fIstrfmon\fR()
function shall place characters into the array pointed to by
.IR s
as controlled by the string pointed to by
.IR format .
No more than
.IR maxsize
bytes are placed into the array.
.P
The format is a character string, beginning and ending in its
initial state, if any, that contains two types of objects:
\fIplain characters\fP,
which are simply copied to the output stream, and \fIconversion
specifications\fP,
each of which shall result in the fetching of zero or more arguments
which are converted and formatted. The results are undefined if there
are insufficient arguments for the format. If the format is exhausted
while arguments remain, the excess arguments are simply ignored.
.P
The application shall ensure that a conversion specification consists
of the following sequence:
.IP " *" 4
A
.BR '%' 
character
.IP " *" 4
Optional flags
.IP " *" 4
Optional field width
.IP " *" 4
Optional left precision
.IP " *" 4
Optional right precision
.IP " *" 4
A required conversion specifier character that determines the
conversion to be performed
.P
The
\fIstrfmon_l\fR()
function shall be equivalent to the
\fIstrfmon\fR()
function, except that the locale data used is from the
locale represented by
.IR locale .
.SS Flags
.P
One or more of the following optional flags can be specified to control
the conversion:
.IP "\fR=\fIf\fR" 8
An
.BR '=' 
followed by a single character
.IR f
which is used as the numeric fill character. In order to work with
precision or width counts, the fill character shall be a single byte
character; if not, the behavior is undefined. The default numeric fill
character is the
<space>.
This flag does not affect field width filling which always uses the
<space>.
This flag is ignored unless a left precision (see below) is specified.
.IP "\fR^\fR" 8
Do not format the currency amount with grouping characters. The
default is to insert the grouping characters if defined for the current
locale.
.IP "\fR+\fR\ or\ \fR(\fR" 8
Specify the style of representing positive and negative currency
amounts. Only one of
.BR '+' 
or
.BR '(' 
may be specified. If
.BR '+' 
is specified, the locale's equivalent of
.BR '+' 
and
.BR '\-' 
are used (for example, in many locales, the empty string if positive and
.BR '\-' 
if negative). If
.BR '(' 
is specified, negative amounts are enclosed within parentheses. If
neither flag is specified, the
.BR '+' 
style is used.
.IP "\fR!\fR" 8
Suppress the currency symbol from the output conversion.
.IP "\fR\-\fR" 8
Specify the alignment. If this flag is present the result of the
conversion is left-justified (padded to the right) rather than
right-justified. This flag shall be ignored unless a field width (see
below) is specified.
.SS "Field Width"
.IP "\fIw\fP" 8
A decimal digit string
.IR w
specifying a minimum field width in bytes in which the result of the
conversion is right-justified (or left-justified if the flag
.BR '\-' 
is specified). The default is 0.
.SS "Left Precision"
.IP "\fR#\fIn\fR" 8
A
.BR '#' 
followed by a decimal digit string
.IR n
specifying a maximum number of digits expected to be formatted to the
left of the radix character. This option can be used to keep the
formatted output from multiple calls to the
\fIstrfmon\fR()
function aligned in the same columns. It can also be used to fill
unused positions with a special character as in
.BR \(dq$***123.45\(dq .
This option causes an amount to be formatted as if it has the number of
digits specified by
.IR n .
If more than
.IR n
digit positions are required, this conversion specification is ignored.
Digit positions in excess of those actually required are filled with
the numeric fill character (see the \fR=\fIf\fR flag above).
.RS 8 
.P
If grouping has not been suppressed with the
.BR '\(ha' 
flag, and it is defined for the current locale, grouping separators are
inserted before the fill characters (if any) are added. Grouping
separators are not applied to fill characters even if the fill
character is a digit.
.P
To ensure alignment, any characters appearing before or after the
number in the formatted output such as currency or sign symbols are
padded as necessary with
<space>
characters to make their positive and negative formats an equal length.
.RE
.SS "Right Precision"
.IP "\fR.\fIp\fR" 8
A
<period>
followed by a decimal digit string
.IR p
specifying the number of digits after the radix character. If the
value of the right precision
.IR p
is 0, no radix character appears. If a right precision is not
included, a default specified by the current locale is used. The
amount being formatted is rounded to the specified number of digits
prior to formatting.
.SS "Conversion Specifier Characters"
.P
The conversion specifier characters and their meanings are:
.IP "\fRi\fP" 8
The
.BR double
argument is formatted according to the locale's international currency
format (for example, in the US: USD 1,234.56). If the argument is
\(+-Inf or NaN, the result of the conversion is unspecified.
.IP "\fRn\fP" 8
The
.BR double
argument is formatted according to the locale's national currency
format (for example, in the US: $1,234.56). If the argument is
\(+-Inf or NaN, the result of the conversion is unspecified.
.IP "\fR%\fP" 8
Convert to a
.BR '%' ;
no argument is converted. The entire conversion specification shall be
.BR %% .
.SS "Locale Information"
.P
The
.IR LC_MONETARY
category of the current locale affects the behavior of this function
including the monetary radix character (which may be different from the
numeric radix character affected by the
.IR LC_NUMERIC
category), the grouping separator, the currency symbols, and formats.
The international currency symbol should be conformant with the ISO\ 4217:\|2001 standard.
.P
If the value of
.IR maxsize
is greater than
{SSIZE_MAX},
the result is implementation-defined.
.P
The behavior is undefined if the
.IR locale
argument to
\fIstrfmon_l\fR()
is the special locale object LC_GLOBAL_LOCALE or is not a valid locale
object handle.
.SH "RETURN VALUE"
If the total number of resulting bytes including the terminating null
byte is not more than
.IR maxsize ,
these functions shall return the number of bytes placed into the array
pointed to by
.IR s ,
not including the terminating NUL character. Otherwise, \-1 shall be
returned, the contents of the array are unspecified, and
.IR errno
shall be set to indicate the error.
.SH ERRORS
These functions shall fail if:
.TP
.BR E2BIG
Conversion stopped due to lack of space in the buffer.
.LP
.IR "The following sections are informative."
.SH "EXAMPLES"
Given a locale for the US and the values 123.45, \-123.45, and
3456.781, the following output might be produced. Square brackets (\c
.BR \(dq[\|]\(dq )
are used in this example to delimit the output.
.sp
.RS 4
.nf

%n         [$123.45]         \fRDefault formatting\fP
           [-$123.45]
           [$3,456.78]
.P
%11n       [    $123.45]     \fRRight align within an 11-character field\fP
           [   -$123.45]
           [  $3,456.78]
.P
%#5n       [ $   123.45]     \fRAligned columns for values up to 99\|999\fP
           [-$   123.45]
           [ $ 3,456.78]
.P
%=*#5n     [ $***123.45]     \fRSpecify a fill character\fP
           [-$***123.45]
           [ $*3,456.78]
.P
%=0#5n     [ $000123.45]     \fRFill characters do not use grouping\fP
           [-$000123.45]     \fReven if the fill character is a digit\fP
           [ $03,456.78]
.P
%\(ha#5n      [ $  123.45]      \fRDisable the grouping separator\fP
           [-$  123.45]
           [ $ 3456.78]
.P
%\(ha#5.0n    [ $  123]         \fRRound off to whole units\fP
           [-$  123]
           [ $ 3457]
.P
%\(ha#5.4n    [ $  123.4500]    \fRIncrease the precision\fP
           [-$  123.4500]
           [ $ 3456.7810]
.P
%(#5n      [ $   123.45 ]    \fRUse an alternative pos/neg style\fP
           [($   123.45)]
           [ $ 3,456.78 ]
.P
%!(#5n     [    123.45 ]     \fRDisable the currency symbol\fP
           [(   123.45)]
           [  3,456.78 ]
.P
%-14#5.4n  [ $   123.4500 ]  \fRLeft-justify the output\fP
           [-$   123.4500 ]
           [ $ 3,456.7810 ]
.P
%14#5.4n   [  $   123.4500]  \fRCorresponding right-justified output\fP
           [ -$   123.4500]
           [  $ 3,456.7810]
.fi
.P
.RE
.P
See also the EXAMPLES section in
\fIfprintf\fR().
.SH "APPLICATION USAGE"
None.
.SH RATIONALE
None.
.SH "FUTURE DIRECTIONS"
Lowercase conversion characters are reserved for future standards use
and uppercase for implementation-defined use.
.SH "SEE ALSO"
.IR "\fIfprintf\fR\^(\|)",
.IR "\fIlocaleconv\fR\^(\|)"
.P
The Base Definitions volume of POSIX.1\(hy2017,
.IR "\fB<monetary.h>\fP"
.\"
.SH COPYRIGHT
Portions of this text are reprinted and reproduced in electronic form
from IEEE Std 1003.1-2017, Standard for Information Technology
-- Portable Operating System Interface (POSIX), The Open Group Base
Specifications Issue 7, 2018 Edition,
Copyright (C) 2018 by the Institute of
Electrical and Electronics Engineers, Inc and The Open Group.
In the event of any discrepancy between this version and the original IEEE and
The Open Group Standard, the original IEEE and The Open Group Standard
is the referee document. The original Standard can be obtained online at
http://www.opengroup.org/unix/online.html .
.PP
Any typographical or formatting errors that appear
in this page are most likely
to have been introduced during the conversion of the source files to
man page format. To report such errors, see
https://www.kernel.org/doc/man-pages/reporting_bugs.html .
